Update with new functions and comments describing them.

[mmh] / h / fmt_scan.h

/*
 * fmt_scan.h -- definitions for fmt_scan()
 */

/*
 * This structure describes an "interesting" component.  It holds
 * the name & text from the component (if found) and one piece of
 * auxilary info.  The structure for a particular component is located
 * by (open) hashing the name and using it as an index into the ptr array
 * "wantcomp".  All format entries that reference a particular component
 * point to its comp struct (so we only have to do component specific
 * processing once.  e.g., parse an address.).
 *
 * In previous implementations "wantcomp" was made available to other
 * functions, but now it's private and is accessed via functions.
 */
struct comp {
    char        *c_name;        /* component name (in lower case) */
    char        *c_text;        /* component text (if found)      */
    struct comp *c_next;        /* hash chain linkage             */
    short        c_flags;       /* misc. flags (from fmt_scan)    */
    short        c_type;        /* type info   (from fmt_compile) */
    union {
        struct tws *c_u_tws;
        struct mailname *c_u_mn;
    } c_un;
    int          c_refcount;    /* Reference count                */
};

#define c_tws c_un.c_u_tws
#define c_mn  c_un.c_u_mn

/*
 * c_type bits
 */
#define CT_ADDR       (1<<0)    /* referenced as address    */
#define CT_DATE       (1<<1)    /* referenced as date       */

/*
 * c_flags bits
 */
#define CF_TRUE       (1<<0)    /* usually means component is present */
#define CF_PARSED     (1<<1)    /* address/date has been parsed */
#define CF_DATEFAB    (1<<2)    /* datefield fabricated */
#define CF_TRIMMED    (1<<3)    /* Component has been trimmed */

extern int fmt_norm;

/* 
 * Hash function for component name.  The function should be
 * case independent and probably shouldn't involve a routine
 * call.  This function is pretty good but will not work on
 * single character component names.  
 */
#define CHASH(nm) (((((nm)[0]) - ((nm)[1])) & 0x1f) + (((nm)[2]) & 0x5f))

/*
 * Find a component in the hash table.
 */
#define FINDCOMP(comp,name) \
                for (comp = wantcomp[CHASH(name)]; \
                     comp && strcmp(comp->c_name,name); \
                     comp = comp->c_next) \
                ;

/*
 * This structure defines one formatting instruction.
 */
struct format {
    unsigned char f_type;
    char          f_fill;
    short         f_width;      /* output field width   */
    union {
        struct comp *f_u_comp;  /* associated component */
        char        *f_u_text;  /* literal text         */
        char         f_u_char;  /* literal character    */
        int          f_u_value; /* literal value        */
    } f_un;
};

#define f_skip f_width          /* instr to skip (false "if") */

#define f_comp  f_un.f_u_comp
#define f_text  f_un.f_u_text
#define f_char  f_un.f_u_char
#define f_value f_un.f_u_value

/*
 * prototypes used by the format engine
 */

/*
 * Create a new format string.  Arguments are:
 *
 * form         - Name of format file.  Will be searched by etcpath(), see that
 *                function for details.
 * format       - The format string to be used if no format file is given
 * default_fs   - The default format string to be used if neither form nor
 *                format is given
 *
 * This function also takes care of processing \ escapes like \n, \t, etc.
 *
 * Returns an allocated format string.
 */

char *new_fs (char *form, char *format, char *default_fs);

/*
 * Compile a format string into a set of format instructions.  Arguments are:
 *
 * fstring      - The format string (the "source code").
 * fmt          - Returns an allocated array of "struct fmt" elements.  Each
 *                struct fmt is one format instruction interpreted by the
 *                format engine.
 * reset        - If set to true, the format compiler will reset the
 *                component hash table.  The component hash table contains
 *                all of the references to message components refered to in
 *                the format instructions.  If you have multiple format
 *                strings that you want to compile and operate on the
 *                same message, this should be set to false.
 *
 * Returns the number of components referenced by the format instructions.
 */

int fmt_compile (char *fstring, struct format **fmt, int reset);

/*
 * Interpret a sequence of compiled format instructions.  Arguments are:
 *
 * format       - Array of format instructions generated by fmt_compile()
 * scanl        - Passed-in character array that will contain the output
 *                of the format instructions.  Is always terminated with
 *                a newline (\n).
 * max          - Maximum number of bytes to be written to "scanl" (in other
 *                words, the buffer size).  Includes the trailing NUL.
 * width        - Maximum number of displayed characters.  Does not include
 *                characters marked as nonprinting or (depending on the
 *                encoding) bytes in a multibyte encoding that exceed the
 *                character's column width.
 * dat          - An integer array that contains data used by certain format
 *                functions.  Currently the following instructions use
 *                dat[]:
 *
 *              dat[0] - %(msg), %(dat)
 *              dat[1] - %(cur)
 *              dat[2] - %(size)
 *              dat[3] - %(width)
 *              dat[4] - %(unseen)
 *
 * The return value is a pointer to the next format instruction to
 * execute, which is currently always NULL.
 */

struct format *fmt_scan (struct format *format, char *scanl, size_t max,
                         int width, int *dat);

/*
 * Free a format structure and/or component hash table.  Arguments are:
 *
 * format       - An array of format structures allocated by fmt_compile,
 *                or NULL.
 * reset        - If true, reset and remove all references in the component
 *                hash table.
 */

void fmt_free (struct format *fmt, int reset);

/*
 * Search for a component structure in the component hash table.  Arguments are:
 *
 * component    - The name of the component to search for.  By convention
 *                all component names used in format strings are lower case,
 *                but for backwards compatibility this search is done in
 *                a case-SENSITIVE manner.
 *
 * This function returns a "struct comp" corresponding to the named component,
 * or NULL if the component is not found in the hash table.
 */

struct comp *fmt_findcomp(char *component);

/*
 * Add a string to a component hash table entry.  Arguments are:
 *
 * component    - The name of the component to add text to.  The component
 *                is searched for in a case-INSENSITIVE manner (note that
 *                this is different than fmt_findcomp()).  If the component
 *                is not found in the hash table, this function will silently
 *                return.
 * text         - The text to add to a component hash table entry.  Note that
 *                if the last character of the existing component
 *                text is a newline AND it is marked as an address
 *                component (the the CT_ADDR flag is set) existing
 *                component buffer is a newline, it will be separated
 *                from previous text by ",\n\t"; otherwise if the last
 *                character of the previous text is a newline it will
 *                simply be seperated by a "\t".  This unusual processing
 *                is designed to handle the case where you have multiple
 *                headers with the same name (e.g.: multiple "cc:" headers,
 *                even though that isn't technically allowed in the RFCs).
 *
 * This function is designed to be called when you start processing a new
 * component.  The function returns the integer value of the hash table
 * bucket corresponding to this component.
 */

int fmt_addcomp(char *component, char *text);

/*
 * Append to an existing component.  Arguments are:
 *
 * bucket       - The hash table bucket corresponding to this component,
 *                as returned by fmt_addcomp().
 * component    - The component to append text to.  Like fmt_addcomp, the
 *                component is searched case-INSENSITIVELY.
 * text         - The text to append to the component.  No special processing
 *                is done.
 *
 * This function is designed to be called when you are processing continuation
 * lines on the same header (state == FLDPLUS).
 */

void fmt_appendcomp(int bucket, char *component, char *text);

/*
 * The implementation of the %(formataddr) function.  This is available for
 * programs to provide their own local implementation if they wish to do
 * special processing (see uip/replsbr.c for an example).  Arguments are:
 *
 * orig         - Existing list of addresses
 * str          - New address(es) to append to list.
 *
 * This function returns an allocated string containing the new list of
 * addresses.
 */

char *formataddr(char *orig, char *str);

/*
 * The implementation of the %(concataddr) function.  Arguments and behavior
 * are the same as %(formataddr).  Again, see uip/replsbr.c to see how you
 * can override this behavior.
 */

char *concataddr(char *orig, char *str);